Novel vaccine antigens against N. gonorrhoeae

淋球菌是性传播感染(STI)淋病的病原体。 全球发病率高，估计每年有8700万病例，生殖道严重 女性的并发症。目前的淋病治疗方法因最近发生的淋病而受到影响 抗生素耐药性。迫切需要一种有效的疫苗来对抗淋病奈瑟菌，但具有保护性。 到目前为止，抗原一直是有限的。我们先前在人类自然状态下的淋球菌转录组的工作 感染描述了淋球菌基因在尿路和阴道灌洗液中表达的差异 自然感染者的样本与相应的淋球菌感染时的mRNA表达的比较 对菌株进行体外培养。我们将这些基因称为“体内表达因子”(IVEF)。我们还报道了， 在感染过程中表达的淋球菌基因中，约有30%是假想蛋白。我们假设 在感染过程中表达和调节的淋球菌假想蛋白包括新的候选抗原 淋病奈瑟菌疫苗。通过基于生物信息学的候选抗原选择策略(CASS) 检查了预测的免疫原性、细胞定位、淋球菌的保守性和结构 为了研究淋球菌假想蛋白的特征，我们确定了36个新的潜在靶点(正在进行的R21AI131004)。 我们研究了最初的一组6个抗原，确认3个是表面暴露蛋白(NGO0690，NGO0948 和NGO1701)，诱导具有补体介导的血清杀菌活性的交叉反应抗体 (SBA)对不同的淋病奈瑟菌株。在初步研究中，这些抗原的组合显示 有望成为淋球菌感染小鼠模型的保护性候选疫苗。保护的相关因素 抗淋病在人类中的作用尚不清楚，但SBA和小鼠阴道定植的减少正在逐步- 结石在临床前淋球菌疫苗评价中的应用。一个例子是(目前最先进的)N。 淋病疫苗候选，2C7 LOS表位(及其模拟表位TCMP2)。引用的其他机制 保护包括依靠抗体抑制细菌在定植时对宿主细胞的黏附或入侵 但这些尚未在人体研究中得到证实。该项目的目标是验证和改进 我们的三个候选淋球菌疫苗抗原的有效性。在目标1中，我们建议使用抗原剂量 和佐剂研究，以实现对我们的候选人和SBA的最佳免疫反应；在目标2中，我们将验证 在淋球菌阴道定植的现有雌性小鼠模型中的保护作用，扩大毒株覆盖范围 包括TMCP2，以及相关的免疫效应机制和保护；在目标3中，我们将定义 假设候选蛋白的功能及其对淋球菌毒力、适合度和 免疫力，这是他们被选为候选疫苗的必要补充。我们的研究将提供新的工具 以及对成功研制淋病奈瑟菌疫苗这一未实现目标的了解。

Neisseria gonorrhoeae is the causative agent of the sexually transmitted infection (STI) gonorrhea, a disease with high morbidity worldwide, estimated at 87 million cases annually, and severe reproductive tract complications in women. Current treatment approaches against gonorrhea are compromised by recent onset of antibiotic resistance. There is a pressing need for an effective vaccine against N. gonorrhoeae, but protective antigens have been limited, so far. Our previous work on the gonococcal transcriptome during human natural infection has described differences in mRNA expression of gonococcal genes in urethral and vaginal lavage samples fromnaturally-infected subjects as compared to mRNA expression when the correspondinggonococcal strains were cultured in vitro. We termed those genes “in vivo-expressed factors” (IVEFs). We also reported that ~30% of the gonococcal genes expressed during infection are hypothetical proteins. We hypothesized that gonococcal hypothetical proteins expressed and regulated during infection include new candidate antigens for a vaccine against N. gonorrhoeae. Through a bioinformatics-based candidate antigen selection strategy (CASS) that examined predicted immunogenicity, cellular localization, conservation in N. gonorrhoeae and structure features of the gonococcal hypothetical proteins, we identified 36 new potential targets (ongoing R21AI131004). We investigated an initial group of 6 antigens, confirming 3 as surface-exposed proteins (NGO0690, NGO0948 and NGO1701) that induced cross-reactive antibodies with complement-mediated serum bactericidal activity (SBA) against diverse N. gonorrhoeae strains. In preliminary studies, a combination of these antigens showed promise as protective vaccine candidates in a mouse model of gonococcal infection. Correlates of protection against gonorrhea in humans are not known but SBA and reduced vaginal colonization in mice are stepping- stones in preclinical gonococcal vaccine evaluation. An example is the (currently most advanced) N. gonorrhoeae vaccine candidate, the 2C7 LOS epitope (and its mimotope TCMP2). Other cited mechanisms of protection include antibody-dependent inhibition of bacterial adhesion or invasion of host cells at the colonization site, but these have yet to be confirmed in human studies. The goal of this project is to validate and improve the efficacy of our three candidates as gonococcal vaccine antigens. In Aim 1, we propose antigen dosing and adjuvant studies to achieve optimal immune responses to our candidates and SBA; in Aim 2 we will validate protection in the available female mouse model of gonococcal vaginal colonization, broaden strain coverage by including TMCP2, and correlate immune effector mechanisms and protection; in Aim 3, we will define the function of the hypothetical protein candidates and their impact on N. gonorrhoeae virulence, fitness and Immunity, a necessary complement for their selection as vaccine candidates. Our studies will provide new tools and knowledge towards the unmet goal of a successful vaccine against N. gonorrhoeae.